Ethical challenges and associated controversies have arisen repeatedly in the context of biomedical HIV prevention trials, leading to the development of intensive models of community and stakeholder participation as a means to finding ethical solutions to difficult dilemmas. Trials of new TB regimens raise challenges similar to those of HIV but have not resulted in the same kind of global controversies. In October 2012 the Stakeholder and Community Engagement Workgroup (SCE-WG) of the Critical Path to TB Drug Regimens (CPTR) issued Good Participatory Practice Guidelines for TB Drug Trials (GPP-TB), based on similar guidelines for HIV. Despite the acceptance of the importance of community engagement and participatory strategies for HIV prevention trials and diffusion of guidelines to the TB context, empirical assessment of the benefits and burdens has languished. We propose to use a Theory of Change (TOC) approach to develop an evaluation process for GPP-TB. First (Aim 1,) we will bring TB drug trials stakeholders together to map a GPP-TB Theory of Change and develop an associated evaluation strategy that is plausible, doable and testable. Second (Aim 2), we will work with a globally diverse group of TB trials implementing sites, conduct formative work to develop and pilot a set of priority outcome measures suitable for an ethical analysis of risks, benefits and social value in TB trials. Collaborating sites have been identified in Vietnam, Peru, and Uganda. This proposal has been developed in collaboration with representatives of the CPTR SCE-WG, the CDC-led TB Trials Consortium (TBTC) and its Community Research Advisory Group (CRAG), and AVAC. Through this study our understanding of how to evaluate GPP as an ethics tool for TB trials will be significantly advanced, positioning us to design and implement a rigorous evaluation of the benefits and costs of GPP-TB and its impact on ethics outcomes.